In this technical field of forming containers, hygiene is a very important issue in order to prevent any risk of contamination of the content of the containers, for example bottles with products that are to be ingested by consumers or applied on the skin of a consumer. In particular, any part in contact with the product intended to fill the containers has to work in an aseptic environment and preferably be isolated from the exterior atmosphere.
In a container forming device, a central rod, such as a stretch rod is used to assist in the deformation of the preform, the stretch rod pushing the bottom of the preform in order to deform the preform in an axial direction, the radial deformation being ensured at the same time by injecting a compressible gaseous fluid or an incompressible liquid in the preform.
The stretch rod is therefore plunged in the preform and might contaminate it if not properly working in a contamination free environment and regularly being cleaned. WO-2011/030183 discloses a device for blowing and stretching a plastic preform, wherein the stretch rod is housed in a tube to be isolated from the exterior atmosphere. The housing is separated and isolated from the chamber, or injection nozzle, by fixed sealing means, meaning that, for properly cleaning the injection device and its stretch rod, the chamber and the housing have to be cleaned separately via two separate cleaning paths for the cleaning products, which complicates the injection device. Furthermore, parts of the injection device remain difficult to clean, in particular around the fixed sealing means, without having to dismantle the injection device.
One of the aims of the invention is to simplify the cleaning of an injection device and guarantying a proper cleaning of all its components via a single cleaning path and without having to dismantle the injection device.